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SSRN 2025年

作者： Li, Huanqing Zhao, Yuhong Song, Zhuo Tian, Xiaolin Dong, Ruifeng Zhang, Yuntao Hou, Hua School of Materials Science and Engineering MOE jointly Collaborative Innovation Center for High-performance Al/Mg based Materials Shanxi Key Laboratory of Intelligent Casting and Advanced Forming for New Materials North University of China Taiyuan030051 China Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology Beijing Beijing100083 China School of Materials Science and Engineering Taiyuan University of Science and Technology Taiyuan030024 China Institute of Materials Intelligent Technology Liaoning Academy of Materials Shenyang110004 China

Modulating serrated grain boundaries (SGB) has the potential to enhance fracture properties in materials. This work investigates the crack behavior at SGB during loading through high-resolution transmission electron microscopy, quasi in-situ electron backscatter diffraction and phase field crystal simulations. Experimental results demonstrate the presence of abundant SGBs in the transition zone of rolled pure magnesium, with nano-crack initiation and propagation at these boundaries driven by basal or prismatic slip at varying angles between the grains. Additionally, large shear strains are observed in the SGB bending regions, and portions of these regions that align with the loading direction impede crack propagation. Previous studies have suggested that a loading direction perpendicular to the grain boundary (GB) promotes intergranular fracture. However, our research demonstrates that the influence of the angle between GB and the loading direction on crack propagation is localized, with previous conclusions valid only within a strain range of 10-27%. Beyond this critical strain, cracks predominantly transgranular propagate in a brittle manner, with a weaker effect in the loading direction. Furthermore, when the angle between SGB and the loading direction is less than 65°, the proportion of the SGB parallel to the loading direction increases, thereby inhibiting intergranular fracture. Additionally, SGB curvature significantly impacts crack extension, with an optimal curvature of approximately 0.151 1/nm for double-serrated grain boundaries that effectively suppresses nano-crack propagation. This work may provide insights into enhancing material fracture strength through the control of SGB. © 2025, The Authors. All rights reserved.

关键词： Crack propagation

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Numerical modeling and simulation for microneedles drug delivery: A novel comprehensive swelling-obstruction-mechanics model

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European Journal of Pharmaceutics and Biopharmaceutics 2025年 206卷 114583页

作者： Yang, Peijing Song, Qinghua Zhang, Lujie Liu, Zhanqiang Ma, Haifeng School of Mechanical Engineering Shandong University Jinan 250061 China State Key Laboratory of Advanced Equipment and Technology for Metal Forming Shandong University Jinan 250061 China Key Laboratory of High Efficiency and Clean Mechanical Manufacture Ministry of Education Jinan 250061 China Key National Demonstration Center for Experimental Mechanical Engineering Education Jinan 250061 China School of Mechanical Electrical & Information Engineering Shandong University Weihai 264209 China

Hydrogel microneedles have attracted significant attention in drug delivery due to their non-invasiveness and efficient administration. However, a thorough understanding of the drug transport mechanism is essential to achieve controlled drug delivery and geometry optimization of microneedles. In this study, a new swelling-obstruction-mechanics model is presented to describe the swelling and drug release behavior of hydrogel microneedles. The model integrates the swelling kinetics, the obstruction scaling of drug molecules, and the mechanical properties of hydrogel and skin and reveals the effects of swelling of the microneedle matrix and drug molecules on drug release. Subsequently, numerical simulations were conducted using the model, which enabled the optimization of hydrogel microneedle design parameters by adjusting the input variables. The results show that the geometric parameters of microneedles, especially the cross-sectional shape, have a significant effect on the drug release performance. Nevertheless, the parameters affect each other and need to be considered in the selection of a variety of factors. Additionally, penetration depth significantly affects drug release efficiency, highlighting the need for auxiliary application devices. In summary, the model advances both theoretical understanding and practical design of hydrogel microneedles, identifying key factors in drug release and optimizing their efficiency and reliability for clinical applications. © 2024 Elsevier B.V.

关键词： Drug delivery Finite element simulation Hydrogel microneedles Mathematical model Mechanical property Swelling and obstruction scaling principle

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Control over Mechanical Properties and Microstructure of BR1500HS Hot-stamped Parts

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Journal of Iron and Steel Research International 2014年第6期21卷 606-613页

作者： Bai-liang ZHUANG Zhong-de SHAN Chao JIANG Xin-ya LI State Key Laboratory of Advanced Forming Technology and Equipment of CAM Jiangsu Institute China Academy of Machinery Science and Technology

The hot stamping processing parameters are of critical importance in transforming ultra-high-strength steel （UHSS） into high-quality parts, which were studied by mechanical properties tests, metallographic observations and calculation analysis method based on hot stamping experiments and numerical simulation technology, the mechanical properties, thickness, dimensional accuracy, and microstructure of the hot formed parts are analyzed to determine the influence of different processing parameters for UHSS parts formed from BR1500HS. The results indicate that the quenching time had the most significant impact on the mechanical properties of the parts, and longer quenching time resulted in better mechanical properties. In addition, the pressing speed had a significant influence on the thick ness of the formed parts, and the part-opening temperature had the most significant effect on the dimensional accura cy of the parts. And to get hot stamped parts with excellent quality, the optimum process conditions should be set as heating temperature of 930 ℃, soaking time of 4 min, stamping force of 7 MPa, pressing speed of 75 mm/s, quench ing time of 15 s, and water-flow rate of 1.1 m/s.

关键词： hot forming processing parameter mechanical property microstructure

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Enhanced high-temperature strength of a Mg-4Sn-3Al-1 Zn alloy with good thermal stability via Mg2Sn precipitation

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Journal of Magnesium and Alloys 2025年

作者： Sun, Wei Deng, Yangchao Hu, Yuhan Zhan, Hongyi Yan, Kun Shuai, Sansan Guo, Enyu Zheng, Zebang Zeng, Guang School of Materials Science and Engineering Central South University Changsha410083 China China Science Lab General Motors Global Research and Development Shanghai 201206 China Department of Materials The University of Manchester ManchesterM13 9PL United Kingdom State Key Laboratory of Advanced Special Steels School of Materials Science and Engineering Shanghai University Shanghai 200444 China School of Materials Science and Engineering Dalian University of Technology Dalian116024 China State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of High-Performance Precision Forming Technology and Equipment School of Materials Science and Engineering Northwestern Polytechnical University P.O.Box 542 Xi'an710072 China

With the growing demand for rapid and cost-effective solutions for lightweight magnesium alloys with excellent high-temperature mechanical properties, we investigated a heat-treatable RE-free magnesium alloy, Mg-4Sn-3Al-1Zn (TAZ431, wt.%), with remarkable thermal stability. The peak-aged TAZ431 alloy exhibits a 15 % increase in high-temperature (230 °C) yield strength, compared to the traditional commercial magnesium alloy, Mg-3Al-1Zn (AZ31, wt.%). In this work, we demonstrate that the basal Mg2Sn precipitates have a more pronounced hindrance effect on the non-basal slip systems, as evidenced by a combination of experiments (in-situ EBSD and dual beam TEM) and numerical simulations (Orowan model and VPSC). The distribution and morphology of Mg2Sn precipitates and cracks are quantitatively analyzed using a range of techniques including in-situ SEM and synchrotron X-ray tomography. Our results reveal that the decohension of grain boundary precipitates significantly promotes the formation of intergranular cracks, leading to ultimate fracture. The research comprehensively explains the impact of particle morphology, orientation, and distribution on precipitation strengthening and fracture modes at elevated temperatures, which is vital for the future development of high-temperature performance magnesium alloys. © 2025

关键词： Cracks

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Deep drawing of cup shell by powder cavity flexible forming technology

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Journal of Central South University 2017年第4期24卷 766-772页

作者： XUE Ya-hong CHEN Ke FAN Cun-jie LUO Jun-ting Education Ministry Key Laboratory of Advanced Forging and Stamping Technology and Science Yanshan UniversityQinhuangdao 066004China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China

A forming method named powder cavity flexible forming was proposed. It is a forming technology which uses powder medium instead of rigid punch or die to form sheet metals. Cup shells were successfully obtained by this technology. The theoretical calculation equation of forming load was obtained through mechanical analysis and the stress state in cup shells was analyzed by finite element simulation. The results show that powder cavity flexible forming technology can improve the forming limit of sheet metal. Compared with rigid die forming process, the thickness reduction in the punch fillet area significantly decreases and the drawing ratio increases from 1.8 to 2.2. The thinning compressive stress in the bottom of cup shell emerges, which makes the bottom of the cup shell in three-dimensional stress state and the stress in punch fillet region decrease due to powder reaction force, which can effectively inhibit the sever thinning of the sheet and prevent the generation of fracture defects.

关键词： cup shell powder cavity flexible forming drawing finite element simulation

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Kinetostatics Analysis of a Novel 6-DOF Parallel Manipulator with Three Planar Limbs and Equipped with Three Fingers

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Chinese Journal of Mechanical Engineering 2014年第5期27卷 919-927页

作者： LU Yi LI Xuepeng College of Mechanical Engineering Yanshan University Key Laboratory of Parallel Robot and Mechatronic System of Hebei Province Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of National Education

It is significant to develop a robot hand with high rigidity by a 6-DOF parallel manipulator（PM）.However,the existing6-DOF PMs include spherical joint which has less capability of pulling force bearing,less rotation range and lower precision under alternately heavy loads.A novel 6-DOF PM with three planar limbs and equipped with three fingers is proposed and its kinematics and statics are analyzed systematically.A 3-dimension simulation mechanism of the proposed manipulator is constructed and its structure characteristics is *** kinematics formulae for solving the displacement,velocity,acceleration of the platform,the active legs and the fingers are *** statics formulae are derived for solving the active forces of PM and the finger *** analytic example is given for solving the kinematics and statics of proposed manipulator and the analytic solved results are verified by the simulation *** is proved from the error analysis of analytic solutions and simulation solutions that the derived analytic formulae are correct and provide the theoretical and technical foundations for its manufacturing,control and application.

关键词： parallel manipulator planar limbs finger kinematics statics

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Shakedown Criterion Employing Actual Residual Stress Field and Its Application in Numerical Shakedown Analysis

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Chinese Journal of Mechanical Engineering 2015年第5期28卷 919-927页

作者： ZOU Zongyuan GUO Baofeng LI Yinxiao JIN Miao ZHAO Shiyan Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education Yanshan University Chinese 91315 People's Liberation Army Troops

Construction of the static admissible residual stress field and searching the optimal field are key tasks in the shakedown analysis methods applying the static theorem. These methods always meet dimension obstacles when dealing with complex problems. In this paper, a novel shakedown criterion is proposed employing actual residual stress field based on the static shakedown theorem. The actual residual stress field used here is produced under a specified load path, which is a sequence of proportional loading and unloading from zero to all the vertices of the given load domain. This ensures that the shakedown behavior in the whole load domain can be determined based on the theorem proposed by K6nig. The shakedown criterion is then implemented in numerical shakedown analysis, The actual residual stress fields are calculated by incremental finite element elastic-plastic analysis technique for finite deformation under the specified load path with different load levels. The shakedown behavior and the shakedown limit load are determined according to the proposed criterion. The validation of the criterion is performed by a benchmark shakedown example, which is a square plate with a central hole under biaxial loading. The results are consistent with existing results in the literatures and are validated by full cyclic elastic-plastic finite element analysis. The numerical shakedown analysis applying the proposed criterion avoids processing dimension obstacles and performing full cyclic elastic-plastic analysis under arbitrary load paths which should be accounted for appearing. The effect of material model and geometric changes on shakedown behavior can he considered conveniently.

关键词： elastoplastic finite element shakedown criterion specified load path actual residual stress field

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Parameter calibration of anisotropic GTN model and forming limit for S600 aluminum alloy sheet

Engineering Research Express

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Engineering Research Express 2025年第2期7卷

作者： Chen, Xiaohua Wang, Zhanshan Zhang, Xuejian Dong, Guojiang Yang, Zhuoyun Yu, Shuang Wang, Yang Yang, Yiru Department of Mechanical and Electrical Engineering Suzhou Vocational Institute of Industrial Technology Suzhou215104 China National-Local Joint Engineering Research Center for Advanced Manufacturing Forming Technology and Equipment Yanshan University Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science Ministry of Education of China Yanshan University Qinhuangdao066004 China

High strength aluminum alloy sheet has obvious anisotropic characteristics and negligible necking in plastic deformation, making its fracture judgment in forming process more difficult than other metals. Taking S600 aluminum alloy sheet as the research object, a coupling model of anisotropic yield criterion and micro-damage theory namely Yld2000-GTN model was established, and its VUMAT subroutine was embedded into ABAQUS software in this study. The proposed model can improve the accuracy of fracture prediction for high-strength aluminum alloy sheet during plastic deformation. Uniaxial tension test and shear test were used to adjust the anisotropic parameters in Yld2000-GTN model. Uniaxial tension test was also employed to adjust damage parameters in Yld2000-GTN model with a new proposed method named sectional type parameter identification method (STPIM) basing on response surface method (RSM) and objective function method (OFM). However, these damage parameters could not accurately simulate the Force-Stroke curves of other notched samples with the highest error up to 18.94%. To correct this error, the relationship between stress triaxiality and damage parameters was further investigated and used to modify damage parameters. Taking the modified parameters into simulation, the prediction error of Force-Stroke curve for all notched samples was reduced to less than 5%. Finally, the theoretical forming limit diagram (FLD) of S600 aluminum alloy sheet was established by the modified parameters, and its accuracy was verified by the bulging test with hemispherical punch. © 2025 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.

关键词： ABAQUS

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Rapid Manufacturing of Sand Molds by Direct Milling

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Tsinghua Science and technology 2009年第S1期14卷 212-215页

作者：董晓丽李新亚单忠德刘丰 Advanced Manufacture Technology Center of China Academy of Machinery Science & Technology State Key Laboratory of Advanced Forming Technology and Equipment

Direct milling of sand molds is an important development in rapid manufacturing of sand molds. Direct milling is an effective method for manufacturing single or small batches of cast parts. This paper describes experimental investigations to find sand blocks with the appropriate strength, to describe wear patterns of different tools (high-speed steel (HSS), carbide, and polycrystalline diamond (PCD) tools), and to analyze sand mold cutting mechanisms. The results show that the PCD tool outperformes the other tools in terms of tool life. Average flank wear and micro-tipping are the dominant tool failure modes in the sand mold milling process. With a flank wear limit of 0.3 mm, the PCD tool works continuously for about 70 h under the experimental conditions. The experimental results show that the cutting mechanism for direct milling sand molds differs from metal cutting.

关键词： milling sand molds tool-wear rapid manufacturing cutting mechanism

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Analysis and Optimization of a Spatial Parallel Mechanism for a New 5-DOF Hybrid Serial-Parallel Manipulator

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Chinese Journal of Mechanical Engineering 2018年第3期31卷 60-68页

作者： Dong-Sheng Zhang Yun-Dou Xu Jian-Tao Yao Yong-Sheng Zhao Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of National Education Yanshan University

Hybrid manipulators have potentially application in machining industries and attract extensive attention from many researchers on the basis of high sti ness and high dexterity. Therefore,in order to expand the application prospects of hybrid manipulator,a novel 5?degree?of?freedom(DOF) hybrid serial?parallel manipulator(HSPM) is proposed. Firstly,the design plan of this manipulator is introduced. Secondly,the analysis of this manipulator is carried out in detail,including kinematics analysis,statics analysis,and workspace analysis. Especially,an amplitude equivalent method of disposing the over?constrained force/couple to the non?overconstrained force/couple is used in the statics analysis. Then,three performance indices are used to optimize the PM. Two of them have been widely used,and the third one is a new index which considers the characteristics of the actuated force. Based on the performance indices,the performance atlas is drawn and the optimal design of the PM is investigated. In order to satisfy the anticipant kinetic characteristics of the PM,the verification of the optimized physical dimension is done and the workspace based on the optimized physical dimension is carried out. This paper will lay good theoretical foundations for application of this novel HSPM and also can be applied to other hybrid manipulators.

关键词： Parallel mechanism Performance indices Optimal design Performance atlas

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